1. Front & Rear Parking Sensor, omni-protection. 2. With buzzer sound indicating distance. ... at rear bumper.Front sensor work when car brake, rear sensor work when car reverse.Buzzer beep warning parking sensor, with "Bi Bi..."Voice ... us, we will reply you in 12hours.2. All parking sensor models support OEM Service, if you want toget your ... , good luck for both of us. Front Parking Sensor VP-240-8S